296 RESEARCHES ON FUNGI 



bodies expand their pilei and shed their spores about noon. This 

 periodicity in fruit-body development is regulated by daylight. 



The response of the stipe to heliotropic and geotropic stimuli in 

 succession results in the pileus being pushed out from crevices between 

 dung-balls into the open and then set in the best position for spore- 

 discharge. 



The spore-discharge period is very brief : it was found to range from 

 about thirty minutes in very small fruit-bodies to about three and a 

 half hours in very large fruit-bodies. 



Chapter II. — In the Plicatilis Sub-type : (1) the gills are parallel- 

 sided and do not have flanges at their edges ; (2) cystidia are present on 

 the gill-sides but, in the unexpanded fruit-body, are not attached by 

 both ends to opposing gills ; (3) the existence of the interlamellar spaces 

 is secured in part by a suitable spacing of the gills where they adjoin 

 the pileus-flesh and at their margins close to the stipe, and in part by 

 the cystidia which act as guards and prevent adjacent gills from touching 

 one another anywhere with their hymenial surfaces ; (4) before spore- 

 discharge begins, the pileus expands umbrella-wise and adjacent gills 

 become widely separated from one another, so that the cystidia project 

 from the gill-sides like pegs ; (5) as the pileus opens, the pileus-flesh 

 and gills become cleft from above downwards, so as to form conspicuous 

 radial sulcations on the top of the pileus ; (6) the basidia are irregu- 

 larly dimorphic-trimorphic ; (7) in the unexpanded pileus there is a 

 short sheath of pileus-flesh surrounding the top of the pileus bounded at 

 its margin by a collar made up of the inner ends of the gills ; and 

 (8) autodigestion of the gills does not take place, so that the spore-freed 

 portions of the gills are not destroyed from below upwards. The 

 absence of autodigestion serves to distinguish the Plicatilis Sub-type 

 from all other Sub-tj^^pes. The only representative of the Plicatilis 

 Sub-tjrpe so far recognised is Coprinus plicatilis. 



The author gives a full account of the structure and mode of spore- 

 discharge of Coprinus plicatilis accompanied by numerous illustrations, 

 and he also provides a taxonomic description of the species. 



Coprinus plicatilis failed to produce fruit-bodies when grown on 

 sterilised horse-dung. The species appears to be graminicolous. 



Coprinus hemerobius is regarded as merely a large form of C. plicatilis. 



The hymenium, made up of dimorphic-trimorphic basidia, large sterile 

 paraphyses, and cystidia, is typically coprinoid in structure. 



The spores have three differing dimensions. In still air they fall at 

 the rate of about 4-29 mm. per second. Their specific gravity is 

 about 1-21. 



In the open, successive crops of fruit-bodies expand their pilei daily 

 about noon or in the early afternoon. This periodicity in fruit-body 

 development is probably regulated by daylight. 



The spores on the gills ripen and are discharged, as in other Coprini, 



